The use of electromagnetic tomographic and spectrographic measurement devices have been identified in U.S. Provisional Patent Application Nos. 61/647,848 and 61/703,488 (each of which is hereby incorporated by reference in its entirety) to locate specified volumes within a material under test and to characterize that volume based upon its electromagnetic characteristics. In order to accomplish this with an instrument that may be readily used in a clinical or field environment requires the combination of apparatus, systems, methods and programs as disclosed in the filings noted above. However, once the basic approaches are disclosed, other applications may be identified and implemented based primarily on changes in the design of the electrode array combined with the previously disclosed art. The ability to change the application or improve on previously disclosed applications also provides the ability to secure data such that the electromagnetic characteristics of specific computational volumes may be readily determined from the electromagnetic properties of measured volumes.
The method to determine the tomographic and spectrographic information for specific volumes of the material under test (MUT) is based on using an equivalent circuit model of the actual measurements made to characterize the impedance characteristics of various sub-volumes of the measured volumes combined with the impedance characteristics of other measured volumes as described below.
The apparatus consisting of the electrode arrangement in the sensor array allows securing of the data for the computation of the electromagnetic characteristic of a volume within the material under test which may then be related to some physical parameter of the MUT. The number of electrodes in the sensor array is related to the number of layers of the MUT to be characterized and the number of volumes of the MUT to be measured. The number of measured volumes is related to the number of computed volumes since the computed volume is a sub-volume of the larger measured volumes. The only measured volume of interest that is identical to the computed value is the smallest measured volume closest to the sensor array. This volume may consist of a volume of the MUT, a combination of the MUT and air, or all air. The composition of the volume depends on whether the sensor array is in contact with the MUT or standing off from the MUT. So as the number of layers of interest of the MUT to be investigated increases, the number of the electrodes in the sensor array increases.
In order to apply the method to secure the measured volume data, various designs and measuring strategies are required to obtain accurate data and secure them in an efficient and timely manner. The method and the apparatus comprising these designs and approaches are the subject of the disclosed invention.